Calling system for radiosignaling



l June 24 .1924.

A 1,499,310 .1.A BETHENOD CALLING SYSTEM "FOR RADIOSIGNALING Filed Aug. 2. 1921 2 sheets-'sheer 1 lll F/y. 4. 25x 2,5

vwemoz JOSEPH BETHENOD June 24, 1924. 41,499,310

J. BETHENOD l CALLING SYSTEM FOR RDIOSIGNALING Filed Aug- 2. 1921 2 Sheets-Sheet, 2

Race/'why 50x .llSEPH BETHENOD @Mlm awmggmj/m` JOSEPH BETHENOD, F PARIS, FRANCE.

CALQLlING SYSTEM FOR RADIOSIGN'ALING.

Application mea August 2, 1921. serii No.' 4saao4.

ymiren STA-res PATENT fol-TICE.'

(seaman Umana 'run 'rnoviions or :una Aer or Manen s, 1921, 41 srar. L isis.)

To all r'whom t may concern. s ,y Be it know-n that I, JOSEPH BETHENOD, a citizen of France, and resident of Paris, France, have invented certain new and usea ful lmpi'ovementsin' Calling Systems for Rediosignaling (for which I have filed applications in France Dec. 12, 1919, and Dec. 23, 1919), of which the following is a speciication acompanied by drawings. io Calling systems for wireless telegraphy or telephony must be as sensitive as possible to the call which is sent outand at the same time it must not res ond to other transmissions and particular y to atmospherics. ln accordance with the present invention,

these two requirements are realized as follows: g1) An energy integrating device is used, an is actuated onlyin case the transmission 2o is of a sufliciently long duration. In this manner, the average power necessary for the operation is reduced and the device is not responsive to short impulses and to atmos-7 pherics that have a periodic character. A selecting and amplifying circuit' is use Assuming that continuous waves are transmitted, the following. arrangement is described for the purpose of illustrating the invention.

Fig. 1 is a diagrain'of connections ofthe preferred forni of m invention.

Fi 2 shows a mo iication of my invention 1n which atuning fork is set into vibration by the received oscillations;

Fig. 3 shows an alternative arrangement of the tuning fork, and y Fig. 4 shows an arrangement comprising a gas thermometi; n accordance 'th the diagram of F 4the call signal is r eived' and amplifie (or amplifier in autodyneV arrangement) generates beats which are detected. The current of musical frequency thus obtained,

actuates a resonance transformer 3, the s eceter 5. Preferably, b this. galvanometer isV of the ballistic type having a long period b3?. means of a tube amplifier 1, rpreferably a resonance amplier; a local heterodyne 2 siderably simplified. The element 4 may be heated by the frequency current receivedby the antenna andy suitablyA amplied. ln this oase no detecting' is necessary.

The characteristic principle of this modication is thecombined use of a thermoelectric element and a contact galvanometer having a long period, the long period system having the vadvantage that it 'integrates the energy and does not respond to disturbances of short duration.

In accordance with another modification, the assembly 4 and 5 may be replaced by an ordinaryRiess thermometer, or preferably, may be arranged in the following manner' as shown by Fig. 4: A horizontal capillary. tube 21 in which a more or less ong mercury .indicator 22 moves, interconnects two bulbs 23 lled with a suitable gas, such as hydrogen, nitrogen,air.' Each of these bulbs contains a filament 24.. One or the other of these filaments may be traversed by a weak current. The sensitiveness of the arrangement is the greater, the weaker the pressure in the tw bulbs. 'dt is independent ofthe atmospheric pressure, but depends on the temperature of the assembly. Partially evacuated bulbs may also be used for this purpose. The. assembly must be enclosed with a heat insulating casing 25. Under the control of the heat that is released, the indis cator is actuated and closes the si alling circuit by means of a suitably provi ed con'- tone ofthe vibratin system correspondingY to the frequency o the receiving current -(simple or double variant depending on whether or not the tuning fork is polarized).

.Due to the lmass tobe vibrated, this arrangement is in the classi of j energy integrators.

Atthe same time, the arrangement has selecting qualities and responds only to transmissions of suicient length. ln this manner, the atmospherics are rendered harmless.

' In the drawing, Fig. 2 shows an illustration of a circuit arrangement for such apparatus. ln this figure, 1 represents the re: ceiving box which may comprise any useful amplifying devices, such as a heterodyne or autodyne source if continuous waves are to be'received. The current of suitably tuned musical l:frequency leaving this box, causes the vibration of a tuning fork-12, whereby a -tone corresponding to this frequency is produced (tone of double frequency if the current is not rectified). The tuning fork is mounted on a resonance box 13 and is controlled, e. g., through the agency of .an electromagnet 11i. This magnet is shown as a simple coil having a laminated metal core, but obviously it mayV have various other forms, such as suitabl arranged multiple coils on the two sides o each prong, etc. lln accordance with the arrangement shown in Fig. 3, the magnet may have the form of a solenoid completely surrounding the two prongs of a narrow tuning-fork 12, these prongs being of nonmagnetized ma etic metal. Furthermore, it may be advisa le to add a device (not shown) adapted to close an electrical circuit when the prongs or the tuning fork attain the maximum amplitude, whereupon a permanent indicator will be actuated. iThis indicator may be visual, and serves to controlv the purely acoustic call. Means may be provided in the orm of a horn, etc., for reinforcing the vibrating asf' sembly.

i Having described my invention, what I claim is:

1. n a calling system for Wireless signaling, the comblnation of receiving circuits and indicating means for received currents, said indicating means comprising a ballistic galvanometer having considerable inertia whereby it is unresponsive to short impulses having a time duration less than that of a dash in the Morse code.

2. ln a calling system for wireless signaling, the combination of receiving circuits, a thermoelectric element connected to the receiving circuitsy and indicating means for received currents, said indicating means having considerable inertia whereby it is unresponsive to short impulses lhaving a time duration less than that of a dash in the Morse code.

3. ln a calling system for wireless signaling, the combination of receiving circuits, a thermoelectric element connected to the receiving circuits and a damped galvanomete'r connected to the thermoelectric element, said system being unresponsive to impulses having a time duration less than that of a dash in the Morse code. 1 l

i. n a calling system for wireless signaling, the combination of receiving circuits, a thermoelectric element connected to the receiving circuits, a damped galvanome'ter connected to the thermoelectrio element and' a relay cooperating with the galvanometer,

said system being unresponsive tol impulses having a time duration less than that of a d ash in the Morse code.

JSEPH l BETHEND'. 

